Chlorotrimethylsilane → (S)-tert-butyl 4-((R)-4-ethoxy-4-oxobutan-2-yl)-2,2-dimethyloxazolidine-3-carboxylate

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Reaction Steps

To CuI (3.36 g, 17.64 mmol) in THF (15 mL) was added at −78° C. MeLi.LiBr (1.5M in ether, 23.5 mL, 35.28 mmol), and the resulting mixture was stirred at −78° C. for 15 min. TMSCl (1.52 mL, 17.64 mmol) and Me2CuLi (generated above) were added in sequence at −78° C. to (S,E)-tert-butyl 4-(3-ethoxy-3-oxoprop-1-enyl)-2,2-dimethyloxazolidine-3-carboxylate (0.88 g, 2.94 mmol), and the resulting mixture was slowly warmed up to rt. Ammonium chloride-ammonium hydroxide buffer (pH ˜8) was added to the reaction mixture. The mixture was extracted with ether, washed with brine, dried over sodium sulfate, and concentrated. Flash chromatography (silica gel, 2:8=ethyl acetate:hexanes) gave (S)-tert-butyl 4-((R)-4-ethoxy-4-oxobutan-2-yl)-2,2-dimethyloxazolidine-3-carboxylate as a clear oil.

Provenance & Evidence